Despite the small supply of homes for sale in Portland, which has especially hampered sales of low-priced homes, the bank said 248 would-be homeowners were able to take advantage of its NeighborhoodLIFT program so far, with a few more in the pipeline.

"Nobody was as surprised as I was," said Heidi Martin, lending manager at the Portland Housing Center, which administered the program in Portland. "I told everybody I thought inventory was going to be a barrier, but it just wasn't."

Wells Fargo launched the program in December, offering first-time homebuyers up to $15,000 toward a down payment. It has launched similar programs in 25 other cities since February 2012, but Portland went through its allocated money faster than any other fund.

"What it really drove home was there are a lot of people out here who can purchase a home," Martin said. "The down payment is clearly the barrier."

Qualifying homebuyers had to make less than 120 percent of the city's median income, buy a home within city limits, and go through training from the Portland Housing Center.

"We had quite a few people who were ready to purchase," said Cobi Jackson, Wells Fargo's regional vice president for community development. "We can just see how that small amount made such a major major major difference."

Participants received a combined $3.7 million in down payment assistance, an increase from the $3.4 million originally allocated.